/**
 * Software License, Version 1.0
 * 
 * Copyright 2003 The Trustees of Indiana University.  All rights reserved.
 * 
 *
 *Redistribution and use in source and binary forms, with or without 
 *modification, are permitted provided that the following conditions are met:
 *
 *1) All redistributions of source code must retain the above copyright notice,
 * the list of authors in the original source code, this list of conditions and
 * the disclaimer listed in this license;
 *2) All redistributions in binary form must reproduce the above copyright 
 * notice, this list of conditions and the disclaimer listed in this license in
 * the documentation and/or other materials provided with the distribution;
 *3) Any documentation included with all redistributions must include the 
 * following acknowledgement:
 *
 *"This product includes software developed by the Community Grids Lab. For 
 * further information contact the Community Grids Lab at 
 * http://communitygrids.iu.edu/."
 *
 * Alternatively, this acknowledgement may appear in the software itself, and 
 * wherever such third-party acknowledgments normally appear.
 * 
 *4) The name Indiana University or Community Grids Lab or NaradaBrokering, 
 * shall not be used to endorse or promote products derived from this software 
 * without prior written permission from Indiana University.  For written 
 * permission, please contact the Advanced Research and Technology Institute 
 * ("ARTI") at 351 West 10th Street, Indianapolis, Indiana 46202.
 *5) Products derived from this software may not be called NaradaBrokering, 
 * nor may Indiana University or Community Grids Lab or NaradaBrokering appear
 * in their name, without prior written permission of ARTI.
 * 
 *
 * Indiana University provides no reassurances that the source code provided 
 * does not infringe the patent or any other intellectual property rights of 
 * any other entity.  Indiana University disclaims any liability to any 
 * recipient for claims brought by any other entity based on infringement of 
 * intellectual property rights or otherwise.  
 *
 *LICENSEE UNDERSTANDS THAT SOFTWARE IS PROVIDED "AS IS" FOR WHICH NO 
 *WARRANTIES AS TO CAPABILITIES OR ACCURACY ARE MADE. INDIANA UNIVERSITY GIVES
 *NO WARRANTIES AND MAKES NO REPRESENTATION THAT SOFTWARE IS FREE OF 
 *INFRINGEMENT OF THIRD PARTY PATENT, COPYRIGHT, OR OTHER PROPRIETARY RIGHTS. 
 *INDIANA UNIVERSITY MAKES NO WARRANTIES THAT SOFTWARE IS FREE FROM "BUGS", 
 *"VIRUSES", "TROJAN HORSES", "TRAP DOORS", "WORMS", OR OTHER HARMFUL CODE.  
 *LICENSEE ASSUMES THE ENTIRE RISK AS TO THE PERFORMANCE OF SOFTWARE AND/OR 
 *ASSOCIATED MATERIALS, AND TO THE PERFORMANCE AND VALIDITY OF INFORMATION 
 *GENERATED USING SOFTWARE.
 */
package cgl.narada.wsinfra.wse.matching.capability;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.xmlbeans.XmlCursor;

import cgl.narada.wsinfra.exception.ProcessingException;
import cgl.narada.wsinfra.schemas.eventing.FilterType;
import cgl.narada.wsinfra.schemas.soap.EnvelopeDocument;
import cgl.narada.wsinfra.wse.matching.MatchingCapability;
/**
    This is a class which implements the TopicMatching Capability.

    @author Shrideep Pallickara
    $Date: 2005/07/29 22:41:30 $
    $Revision: 1.3 $
*/


public class RegularExpressionMatchingCapability extends MatchingCapability {
  private static final MatchingCapability instance = new RegularExpressionMatchingCapability();

  private final 
  String dialect = "http://www.naradabrokering.org/RegularExpressionMatching";
  
  private String moduleName = "RegularExpressionMatchingCapability: ";

  private RegularExpressionMatchingCapability() {}
  
  
  public static MatchingCapability getInstance() {
    return instance;
  }

  /** Retrieves the name associated with this capability. */
  public String getCapabilityName() {
    return moduleName;
  }

  /** Retrieves the dialects associated with the matching capability */
  public String getDialect() {
    return dialect;
  }


  /** Perform the matching operation.
      @return true If there is a match
      @return false If there isn't a match */
  public boolean 
  performMatching(EnvelopeDocument envelopeDocument, FilterType filter) 
    throws ProcessingException {
    //System.out.println(moduleName + "Received Notification to match.");

    checkEnvelopeForProblems(envelopeDocument);
    String constraint = checkFilterForProblems(filter);
    Pattern regExPattern = getPattern(constraint);

    XmlCursor xmlCursor = envelopeDocument.newCursor();
    
    String content = xmlCursor.xmlText();
    boolean matchingSuccess = evaluateRegularExpression(regExPattern, content);
    
    if (matchingSuccess) {
      System.out.println(moduleName + "Match Found.");
    }

    xmlCursor.dispose();
    return matchingSuccess;
  }


  private Pattern getPattern(String constraint) throws ProcessingException {
    if (constraint == null) {
      throw new ProcessingException(moduleName + 
				    "The specified constraint is NULL");
    }
    
    Pattern pattern = Pattern.compile(constraint);
    return pattern;
  }


  private boolean 
  evaluateRegularExpression(Pattern regExPattern,  String contentSynopsis) 
    throws ProcessingException {
    if (regExPattern == null) {
      throw new ProcessingException(moduleName + 
				    "The specified RegEx pattern is NULL");
    }

    if (contentSynopsis == null) {
      throw new ProcessingException(moduleName + 
				    "The specified Content is NULL");
    }
    Matcher matcher = regExPattern.matcher(contentSynopsis);
    matcher.reset();
    return matcher.find();
  }

}
